The Macintosh 128K, released initially as simply the "Apple Macintosh" (without the 128k designation), is the original AppleMacintoshpersonal computer. Its beige case contained a 9 in (23 cm) monitor and came with a keyboard and mouse. A handle built into the top of the case made it easier for the computer to be lifted and carried. It had an initial selling price of US$2,495 (US$5,595 adjusted for inflation). The Macintosh was introduced by the now famous $900,000 television commercial by Ridley Scott, "1984", that most notably aired on CBS during the third quarter of Super Bowl XVIII on January 22, 1984.[1] The sales of the Macintosh were strong from its initial sales release on January 24, 1984 and reached 70,000 units on May 3, 1984.[7] After its successor, the Macintosh 512K, was introduced, it was rebadged as the Macintosh 128K.

The Macintosh was designed to achieve adequate graphics performance, which had previously required hardware costing over US$100,000, a price inaccessible to the middle class. This narrow goal resulted in an efficient design which traded off expandability but met or exceeded the baseline performance of its competitors.[8][9]

The centerpiece of the machine was a Motorola 68000microprocessor running at 7.8336 MHz, connected to 128 KB RAM shared by the processor and the display controller. The boot procedure and some operating system routines were contained in an additional 64 KBROM chip. Apple did not offer RAM upgrades.

The 68000 and video controller took turns accessing DRAM every four CPU cycles during display of the frame buffer, while the 68000 had unrestricted access to DRAM during vertical and horizontal blanking intervals. Such an arrangement reduced the overall performance of the CPU as much as 35% for most codes as the display logic often blocked the CPU's access to RAM. This made the machine appear to run more slowly than several of its competitors, despite the nominally high clock rate.

Back case of an unaltered original Macintosh (sold from January–November 1984). Those made after November, 1984 have the label "Macintosh 128k" on the back of the case.

The built-in display was a one-bit black-and-white, 9 in (23 cm) CRT with a fixed resolution of 512×342 pixels, establishing the desktop publishing standard of 72 PPI[citation needed]. Expansion and networking were achieved using two non-standard RS-422DE-9 serial ports named "printer" and "modem"; they did not support hardware handshaking. An external floppy disk drive could be added using a proprietary connector (19 pin D-sub). The keyboard and mouse used simple proprietary protocols, allowing some third-party upgrades. The original keyboard had no arrow keys, numeric keypad or function keys. This was an intentional decision by Apple, as these keys were common on older platforms and it was thought that the addition of these keys would encourage software developers to simply port their existing applications to the Mac, rather than design new ones around the GUI paradigm.[10] Later, Apple would make a numeric keypad available for the 128k Mac. The keyboard sold with the still later Macintosh Plus model would include the keypad as well as arrow keys. As with the Apple Lisa before it, the mouse had only a single button. Standard headphones could also be connected to a monaural jack. Apple also offered their 300 and 1200 bit/s modems originally released for the Apple II line. Initially, the only printer available was the Apple ImageWriter, a dot matrix printer which was designed to produce 144dpi WYSIWYG output from the Mac's 72dpi screen. Eventually, the LaserWriter and other printers were capable of being connected using AppleTalk, Apple's built-in networking system.

The Macintosh contained a single 400 KB, single-sided 3.5-inchfloppy disk drive, dedicating no space to other internal mechanical storage. The Mac OS was disk-based from the beginning, as RAM had to be conserved, but this "Startup Disk" could still be temporarily ejected. (Ejecting the root filesystem remained an unusual feature of the Classic Mac OS until System 7.) One floppy disk was sufficient to store the System Software, an application, and the data files created with the application. Indeed, the 400 KB drive capacity was larger than the PC XT's 360 KB 5.25-inch drive. However, more sophisticated work environments of the time required separate disks for documents and the system installation. Due to the memory constraints (128 KB) of the original Macintosh, and the fact that the floppies could hold 400 KB, users frequently had to swap disks in and out of the floppy drive. For this reason, external floppy drives were frequently used. The Macintosh External Disk Drive (mechanically identical to the internal one, piggybacking on the same controller) was a popular add-on at US$ 495. Third-party hard drives were considerably more expensive and connected to the slower serial port (as specified by Apple), though a few manufacturers chose to use the faster non-standard floppy port. The 128K can only use the original Macintosh File System for storage.

The unit did not include a fan, relying instead on convection cooling, which made it quiet while in operation. Steve Jobs insisted that the Macintosh ship without a fan, which persisted until the introduction of the Macintosh SE in 1987. This was allegedly a source of many common, costly component failures in the first four Macintosh models. This was enough of a problem to prompt the introduction of a third-party, external cooling fan. This fan unit fitted inside the Macintosh's carrying-handle slot and produced a forced draft through the computer's existing ventilation holes.[11]

The Macintosh shipped with the very first System and Finder application, known to the public as "System 1.0" (formally known as System 0.97, Finder 1.0). The original Macintosh saw three upgrades to both before it was discontinued. Apple recommends System 2.0 and Finder 4.2, with System 3.2 and Finder 5.3 as the maximum. System 4.0 officially dropped support for the Macintosh 128K as evidenced by its distribution on 800 KB floppy disks, which the 128K could not use.

The applications MacPaint and MacWrite were bundled with the Mac. Other programs available included MacProject, MacTerminal and Microsoft's Word. Programming languages available at the time included MacBASIC, MacPascal,[12] and the Macintosh 68000 Development System.[13] The Macintosh also came with a manual and a unique guided tour cassette tape which worked together with the guided tour diskette as a tutorial for both the Macintosh itself and the bundled applications, since almost all users had never used a mouse before, much less manipulated a graphical user interface.

The computer was released in January 1984 as simply the Apple Macintosh. Following the release of the Macintosh 512K in September, which expanded the memory from 128 KB to 512 KB, the original Macintosh was re-branded Macintosh 128K and nicknamed the 'thin Mac'. The new 512K model was nicknamed the 'fat Mac'. While functionally the same, as closed systems, the Macintosh and Macintosh 128K were technically two different computers, with the re-badged 128K containing a completely redesigned logicboard to easily accommodate both 128 KB and 512 KB RAM configurations during manufacture. Though the RAM was still permanently soldered to the logicboard, the new design allowed for easier (though unsanctioned) third-party upgrades to 512 KB. In addition, most of the newer models contained the 1984 revision B of the ROM to accommodate changes in the 400 KB floppy disk drive.[14]

The increased RAM of the 512K was vitally important for the Macintosh as it finally allowed for more powerful software applications, such as the then-popular program Microsoft Multiplan. However, Apple continued to market the 128K for over a year as an entry-level computer, the mid-level 512K and high end Lisa (and claiming it could be easily expanded should the user ever need more RAM).

The Macintosh 128K was not upgradable by the user and only Apple service centers were permitted to open the case.[15] All accessories were external, such as the MacCharlie that added PC compatibility.[16] There was no provision for adding internal storage, more RAM or any upgrade cards. Improving on the hard-wired RAM thus required a motherboard replacement (which was priced similarly to a new computer), or a third-party chip replacement upgrade, which was not only expensive but would void Apple's warranty. The difficulty of fitting software into its limited free memory, coupled with the new interface and event driven programming model, discouraged software vendors from supporting it, leaving the 128K with a relatively small software library. Whereas the Macintosh Plus, and to a lesser extent the Macintosh 512K, are compatible with much later software, the 128K is limited to specially crafted programs. A stock Mac 128K with the original 64K ROM cannot use Apple's external 800 KB drive with HFS, nor Apple's HD20 hard drive. A Mac 128K that has been upgraded with the newer 128K ROM (A Macintosh 128Ke) can use internal and external 800 KB drives with HFS, as well as the HD20. Both can print on an AppleShare network, but neither can do file sharing because of their limited RAM.

Apple did provide an expensive "official" upgrade path for the Macintosh 128K, which included a motherboard replacement effectively making it a Macintosh 512K, for the price of US$ 995.[17][18] Additionally, Apple offered an 800 K floppy disk drive kit, including updated 128K ROMs. Finally, a Mac 128K could be upgraded to a Macintosh Plus by swapping the logicboard as well as the case back (to accommodate the slightly different port configuration) and optionally adding the Macintosh Plus extended keyboard. Any of the kits could be purchased alone or together at any time, to upgrade the Macintosh 128K piecemeal or all-at-once. All upgrades were required to be performed by professional Apple technicians.[19]

BYTE found the hardware and software design (which it predicted would be "imitated but not copied") impressive, but criticized the lack of a standard second disk drive. It predicted that the computer would popularize the 3 1/2" disk-drive standard, that the Macintosh would improve Apple's reputation, and that it "will delay IBM's domination of the personal computer market". The magazine concluded that the Macintosh was "the most important development in computers in the last five years. [It] brings us one step closer to the ideal of computer as appliance".[15]